Question to the Department for Transport:

To ask the Secretary of State for Transport, what plans his Department has to improve roadside air quality across the UK by incorporating diesel particulate filters during the MOT testing process.

The Department for Transport ensures good practice in the regulation of particulate matter emitted from vehicles by reviewing the best available evidence and commissioning research to inform future standards for new vehicles. This includes world-leading research commissioned by the Department to better understand emissions from brake and tyre wear, which is now estimated to account for the majority of particulate matter originating from road vehicles.

Checks for the proper functioning of diesel particulate filters already form part of the MOT test and are explicitly mentioned as an item to be checked in the MOT inspection manual. Where emission control equipment fitted by the manufacturer is missing, obviously modified or obviously defective, the vehicle should receive a “Major” failure and not pass the MOT test. Guidance on the implications of modifying a vehicle’s emissions system has been issued by the Department.

The Department has carried out research to assess whether new measurement equipment could be used to improve the assessment of emissions within the MOT test and roadside checks. This included equipment for detection of removed or damaged diesel particulate filters. Results of this research will be considered for any future changes to the MOT emissions test.

The Driver and Vehicle Standards Agency (DVSA) conducts roadside enforcement inspections nationally using specialist equipment to detect manipulations to vehicle systems and components. A driver using a vehicle on a public road where the diesel particulate filter has been removed may be issued with a prohibition or fixed penalty. Furthermore, the Market Surveillance Unit, within the DVSA, may prosecute a company or individual that carries out an emissions tampering service such as removal of a diesel particulate filter for vehicles used on the road.